Modular audio systems and related assemblies and methods

Modular audio systems comprise two speaker assemblies and a wiring system. Each speaker assembly may comprise a speaker and an audio jack integral to each speaker assembly. The wiring system comprises a first wiring assembly comprising two audio jacks configured to connect to the audio jacks of the two speaker assemblies and two wires connected to the two audio jacks at first ends of the two wires. Headphone assemblies may comprise two speaker assemblies and a headband configured for removable attachment to the speaker assemblies. Each speaker assembly may comprise an attachment structure configured for attachment to another device or structure, wherein the attachment structure of each speaker assembly of the two speaker assemblies comprises a frustoconical surface and two first attachment features comprising elongated features on the frustoconical surface.